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Getting your well water tested in Wisconsin

Use a lab Wisconsin certifies, or a mail-in kit. Across the state, the ones worth testing for are nitrate and manganese, plus bacteria every year.

Compare lab tests Find my county

About 1,802,000 people in Wisconsin get their water from a private well, about 3 in 10 residents.

Three ways to get tested, cheapest first.

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A lab Wisconsin certifies

The state's list of labs certified for drinking water. Many sell bottles you pick up or get by mail, and their results count for a home sale or loan.

Labs certified by Wisconsin
3

A mail-in kit

Order online, fill the bottles at your kitchen tap and get results by email in about a week. Full well tests run about $210 to $220.

Compare kits for Wisconsin
Buying a house or drilling a new well in Wisconsin?

Under NR 812.46, the well driller must collect a water sample from any new or reconstructed potable well within 30 days of completion and have it tested for coliform bacteria by a certified lab.

Look up a well's drilling report

What turns up in Wisconsin wells.

Share of tested wells over the limit, from lab tests the USGS, EPA and state agencies collected since 2000. Your own well needs its own test.

Tested wells over the limit, statewide
Nitrate8%923 of 2,875Manganese7%17 of 249Arsenic5%11 of 222Lead1%2 of 220Uranium1%1 of 197Radon0%0 of 96Fluoride0%0 of 200
GermsTest every year, whatever the chart says
Coliform bacteria22%18 of 81
StainsNot a health risk
Iron stains30%77 of 260

Rare: under 5%Worth checking: 5 to 15%Widespread: 15%+

Lab results: Water Quality Portal (USGS and EPA)

The nitrate figure comes from a 2016 random sample of private wells. The public lab data for Wisconsin put it at 32% of tested wells, but those wells were picked by research and monitoring programs, not at random.

Where it shows up most

  • Nitrate shows up most in Dodge County (about 1 in 3 wells), St. Croix County (about 1 in 3 wells), Marathon County (about 1 in 3 wells).

Find your county.

5 counties have a full report with local test results and well depths.

DanePortageShawanoWaukeshaWaupaca
Every county in Wisconsin: people on wells and typical depth
CountyPeople on private wellsShare of residentsTypical well depth
Waukesha County150,15137%150 ft
Dane County71,80613%180 ft
Marathon County56,37241%140 ft
Washington County52,93439%171 ft
Racine County48,98025%125 ft
St. Croix County45,71249%160 ft
Walworth County45,01042%98 ft
Kenosha County44,85027%117 ft
Outagamie County42,89522%170 ft
Brown County42,27416%183 ft
Rock County36,66222%140 ft
Chippewa County36,01854%68 ft
Winnebago County35,39021%145 ft
Ozaukee County34,93438%190 ft
Fond du Lac County33,63432%165 ft
Portage County33,32247%84 ft
Wood County32,34644%63 ft
Polk County31,50170%109 ft
Sheboygan County31,46327%180 ft
Dodge County31,23835%148 ft
Jefferson County30,58536%143 ft
Waupaca County30,45759%98 ft
Oconto County29,12975%105 ft
Oneida County28,46075%62 ft
La Crosse County28,23123%108 ft
Barron County27,24958%80 ft
Eau Claire County26,19725%95 ft
Manitowoc County25,75732%143 ft
Sauk County25,72439%143 ft
Columbia County25,52044%148 ft
Shawano County25,50662%121 ft
Dunn County23,99453%104 ft
Marinette County23,75657%112 ft
Monroe County22,68249%100 ft
Clark County22,42565%95 ft
Milwaukee County20,0942%200 ft
Waushara County19,91881%101 ft
Vilas County19,82186%60 ft
Pierce County19,66947%200 ft
Door County19,65465%241 ft
Grant County19,54638%240 ft
Vernon County18,46560%220 ft
Adams County16,91382%62 ft
Lincoln County16,79059%73 ft
Green County16,70745%175 ft
Douglas County16,68738%129 ft
Juneau County16,07560%63 ft
Trempealeau County16,01952%101 ft
Taylor County14,12371%93 ft
Sawyer County14,05578%79 ft
Marquette County13,76588%116 ft
Burnett County13,54382%88 ft
Jackson County12,95761%80 ft
Washburn County12,07773%84 ft
Kewaunee County11,91558%162 ft
Bayfield County11,74672%96 ft
Calumet County11,66622%180 ft
Langlade County11,53959%68 ft
Green Lake County10,78057%147 ft
Iowa County10,66145%227 ft
Richland County10,27459%140 ft
Price County9,70569%70 ft
Rusk County9,61768%60 ft
Buffalo County9,08468%92 ft
Lafayette County8,39151%220 ft
Crawford County8,08650%225 ft
Ashland County6,72442%114 ft
Forest County6,49171%70 ft
Pepin County4,79065%118 ft
Florence County3,81484%84 ft
Iron County3,69460%80 ft
Menominee County2,79866%62 ft

Questions people ask about well water in Wisconsin

Does Wisconsin require private wells to be tested?

Under NR 812.46, the well driller must collect a water sample from any new or reconstructed potable well within 30 days of completion and have it tested for coliform bacteria by a certified lab.

Where can I get my well water tested in Wisconsin?

Otherwise, use a lab certified by Wisconsin for drinking water. The state's list is linked on this page.

Where these numbers come from

  • How many people use wells: EPA estimates from the 2020 Census.
  • Lab tests: Water Quality Portal (USGS and EPA), well samples since 2000.
  • Nitrate: Wisconsin DATCP, Agricultural Chemicals in Wisconsin Groundwater (2017).
  • State programs and links: Department of Natural Resources (DNR).